On the calculation of Lorenz numbers for complex thermoelectric materials
Abstract
A first-principles informed approach to the calculation of Lorenz numbers for complex thermoelectric materials is presented and discussed. Example calculations illustrate the importance of using accurate band structures and energy-dependent scattering times. Results obtained by assuming that the scattering rate follows the density-of-states show that in the non-degenerate limit, Lorenz numbers below the commonly assumed lower limit of 2(kB/q)2 can occur. The physical cause of low Lorenz numbers is explained by the shape of the transport distribution. The numerical and physical issues that need to be addressed in order to produce accurate calculations of the Lorenz number are identified. The results of this study provide a general method that should contribute to the interpretation of measurements of total thermal conductivity and to the search for materials with low Lorenz numbers, which may provide improved thermoelectric figures of merit, zT.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 01, 2018
- Source ID
- 10.1063/1.5009939
Entities
People
- Jesse Maassen
- Mark S. Lundstrom
- Vahid Askarpour
- Xufeng Wang
Organizations
- Canadian Network for Research and Innovation in Machining Technology, Natural Sciences and Engineering Research Council of Canada
- Dalhousie University
- Purdue University